Generally, communication cables comprise a core of insulated conductors ranging from a very small number to a very large numbers of conductors. The core is generally surrounded by a MYLAR wrap then usually a metallic sheath and an outer sheath of, for example, polyethylene. The metallic sheath may be of suitable material for the environment in which the cable is to be used, such as aluminum or various steel alloys, or it may be eliminated altogether.
In reclaiming the component elements of such a cable, it is customary to strip the metallic and plastic outer sheaths lengthwise of the cable on a continuous basis. In U.S. Pat. No. 3,175,430 of Smith et al there is shown an arrangement for accomplishing this, in which the element for cutting the outer sheath comprises a blade having a shoe which rides between the core and the sheath. Such spade or plow type cutters have several disadvantages among which are the inability to operate well with very small, e.g. one inch, diameter cables. Further it can be seen that the cutter is located beyond the cable driving wheels, hence, being in a region of less than maximum support for the cable, it is difficult to adjust accurately as to depth of cut. Also, to prevent buckling of the cable between drive wheels and cutter, it is necessary to add additional support means for the cable in the region of the cutter. Such a cutter arrangement only cuts the sheath on one side, and, although not clearly shown in the Smith et al patent, the core must be pulled from the slit circular sheath which, especially in the case of gel filled cable, can present difficulties.
This latter shortcoming is not the case in the apparatus shown in U.S. Pat. No. 3,817,132 of Emery et al, wherein the sheath is cut lengthwise on two sides of the cable. However, the mechanism of the Emery et al patent employs a show for each cutter, thus making operation on small size cables difficult. In addition, at the point of cutting, the only support for the cable along the plane of the cut is the second cutter, which makes it difficult to achieve a precise depth of cut since, as can be appreciated, the cutters are, in effect pushing against each other. Preciseness of the cut is desirable since, if the cut is too shallow, the sheath will not be completely cut through, whereas, if the cut is too deep, the individual wires in the core may be cut or tangled, causing a bunching at the cutter and subsequent stoppage.
The Emery et al patent discloses the use of rotatable cutters, which have their own unique disadvantages. Unless such cutters are extremely sharp, and maintained thus, a rotating cutter will dent, but not reliably cut, a particularly tough metal sheath. A great deal of cutter pressure on the cable is needed to insure a clean cut, but such pressure deforms the cable, and, once the metallic sheath is cut, the cable tends to spring back, causing the cutter to cut into the core and its individual wires. Where as in Emery et al, the two cutters are pushing against each other, this can lead to a great deal of damage to the cable, and possibly the cutters and the machine.
It often happens that aerial cable is to be reclaimed. Aerial cable includes, in addition to the cable components already discussed, a continuous support or strength member of steel wire rope, for example, enclosed within the outer plastic sheath, but otherwise separated from the remainder of the cable. Obviously the various arrangements thus far discussed require that the wire rope be removed prior to their operation on the cable, since they make no accommodation for the rope. An apparatus that is capable of removing the wire rope simultaneously with the removal of the metallic and plastic sheaths of the cable is obviously to be preferred.